This invention relates in general to vehicular driveshaft assemblies and in particular to a method of forming tubing around a tube seal during the manufacture of a splined connection between first and second members of a driveshaft assembly.
Drive train systems are widely used for generating power from a source and for transferring such power from the source to a driven mechanism. Frequently, the source generates rotational power, and such rotational power is transferred from the source to a rotatably driven mechanism. For example, in most land vehicles in use today, an engine/transmission assembly generates rotational power, and such rotational power is transferred from an output shaft of the engine/transmission assembly through a driveshaft assembly to an input shaft of an axle assembly so as to rotatably drive the wheels of the vehicle. To accomplish this, a typical driveshaft assembly includes a hollow cylindrical driveshaft tube having a pair of end fittings, such as a pair of tube yokes, secured to the front and rear ends thereof. The front end fitting forms a portion of a front universal joint that connects the output shaft of the engine/transmission assembly to the front end of the driveshaft tube. Similarly, the rear end fitting forms a portion of a rear universal joint that connects the rear end of the driveshaft tube to the input shaft of the axle assembly. The front and rear universal joints provide a rotational driving connection from the output shaft of the engine/transmission assembly through the driveshaft tube to the input shaft of the axle assembly, while accommodating a limited amount of angular misalignment between the rotational axes of these three shafts.
Not only must a typical drive train system accommodate a limited amount of angular misalignment between the source of rotational power and the rotatably driven device, but it must also typically accommodate a limited amount of relative axial movement therebetween. For example, in most vehicles, a small amount of relative axial movement frequently occurs between the engine/transmission assembly and the axle assembly when the vehicle is operated. To address this, it is known to provide a slip joint in the driveshaft assembly. A typical slip joint includes first and second members that have splines formed thereon that cooperate with one another for concurrent rotational movement, while permitting a limited amount of axial movement to occur. One type of slip joint that is commonly used in conventional driveshaft assemblies is a sliding spline type slip joint.
A typical sliding spline type of slip joint includes male and female members having respective pluralities of splines formed thereon. The male member (often referred to as the yoke shaft) is generally cylindrical in shape and has a plurality of outwardly extending splines formed on the outer surface thereof. The male member may be formed integrally with or secured to an end of the driveshaft assembly described above. The female member (often referred to as the slip yoke), on the other hand, is generally hollow and cylindrical in shape and has a plurality of inwardly extending splines formed on the inner surface thereof. The female member may be formed integrally with or secured to a yoke that forms a portion of one of the universal joints described above. To assemble the slip joint, the male member is inserted within the female member such that the outwardly extending splines of the male member cooperate with the inwardly extending splines of the female member. As a result, the male and female members are connected together for concurrent rotational movement. However, the outwardly extending splines of the male member can slide relative to the inwardly extending splines of the female member to allow a limited amount of relative axial movement to occur between the engine/transmission assembly and the axle assembly of the drive train system.
As is well known in the art, most slip joint assemblies are provided with one or more seals to prevent the entry of dirt, water, and other contaminants into the region where the splined members engage one another. Such contaminants can adversely affect the operation of the slip joint assembly and cause premature failure thereof. Typically, such a seal includes a flexible boot having a lip portion that engages the outer cylindrical surface of the end portion of the slip yoke to prevent contaminants from entering into the inner splined region where the slip yoke engages with a mating splined component of the drive train assembly. Proper functioning and placement of the boot requires machining of both the male and female driveshaft members to provide an area for the boot to be attached to the driveshaft assembly in a secure manner that prevents contaminants from entering the lubricated area. Consequently, the additional machining makes the driveshaft assembly expensive to manufacture. Additionally, the boot is susceptible to failure because of its external positioning. Thus, it would be desirable to provide an improved method of sealing the driveshaft which inexpensively and efficiently protects the slip joint from contamination.